Interbody spacer

ABSTRACT

An interbody spacer is provided including a body portion defining a longitudinal axis. The body portion includes a distal end portion, a proximal end portion, opposed side surfaces that extend between the distal and proximal end portions, and top and bottom surfaces configured and adapted to engage vertebral bodies. The interbody spacer includes first orifices defined through the top surface. The first orifices include orifices having first and second cross-sectional configurations and the first orifices are arranged in rows extending along the longitudinal axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patent application Ser. No. 15/007,879, filed on Jan. 27, 2016, which claims priority to, and the benefit of, U.S. Provisional Patent Application Ser. No. 62/108,197, filed on Jan. 27, 2015, U.S. Provisional Patent Application Ser. No. 62/196,371, filed on Jul. 24, 2015, and U.S. Provisional Patent Application Ser. No. 62/240,662, filed Oct. 13, 2015. The entire contents of each of these prior applications are hereby incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to an apparatus for treating spinal conditions, and more particularly, to an interbody spacer and a method of use therefor.

Background of Related Art

The human spinal column is a highly complex structure. It includes twenty-four discrete bones, known as vertebrae, coupled sequentially to one another to house and protect critical elements of the nervous system. The vertebrae interlock with one another to form a spinal column. Each vertebra has a cylindrical bony body (vertebral body), two pedicles extending from the vertebral body, a lamina extending from the pedicles, two wing-like projections extending from the pedicles, a spinous process extending from the lamina, a pars interarticularis, two superior facets extending from the pedicles, and two inferior facets extending from the lamina.

The vertebrae are separated and cushioned by thin pads of tough, resilient fiber known as inter-vertebral discs. Inter-vertebral discs provide flexibility to the spine and act as shock absorbers during activity. A small opening (foramen) located between each vertebra allows passage of nerves. When the vertebrae are properly aligned, the nerves pass through without a problem. However, when the vertebrae are misaligned or a constriction is formed in the spinal canal, the nerves get compressed and may cause back pain, leg pain, or other neurological disorders.

For many reasons, such as aging and trauma, the intervertebral discs can begin to deteriorate and weaken, potentially resulting in chronic pain, degenerative disc disease, or even tearing of the disc. Ultimately, the disc may deteriorate or weaken to the point of tearing and herniation, in which the inner portions of the disc protrude through the tear. A herniated disc may press against, or pinch, the spinal nerves, thereby causing radiating pain, numbness, tingling, and/or diminished strength or range of motion.

Many treatments are available to remedy these conditions, including surgical procedures in which one or more damaged intervertebral discs are removed and replaced with a prosthetic. After a partial or complete discectomy, the normally occupied space between adjacent vertebral bodies is subject to collapse and/or misalignment due to the absence of all or part of the intervertebral disc. In such situations, the physician may insert one or more prosthetic spacers between the affected vertebrae to maintain normal disc spacing and/or the normal amount of lordosis in the affected region.

Typically, a prosthetic implant is inserted between the adjacent vertebrae and may include pathways that permit bone growth between the adjacent vertebrae until they are fused together. However, there exists a possibility that conventional prosthetic implants may be dislodged and moved from their desired implantation location due to movement by the patient before sufficient bone growth has occurred.

Bone growth is a key factor in ensuring adequate retention of the implant to the vertebra. Specifically, bone ingrowth within and around the prosthetic implant promotes fusion between the adjacent vertebra, thereby strengthening the joint therebetween. However, conventional implants do not allow optimal space for bone ingrowth. In these instances, as the prosthetic implants do not mimic bone density of the adjacent vertebra, the body may reject the implant, and non-union (i.e., no fusion) may occur.

Conventional prosthetic implants are typically constructed in a manner that inhibits bone ingrowth, particularly those that include no spaces or avenues for such bone growth to occur within and around the prosthetic implant. The lack of fusion may allow the implant to become dislodged or moved from its desired location. Additionally, in the instances where the prosthetic implant includes a lumen for the packing of ingrowth material, the material is often able to dislodge from the lumen, and in some instances, from the implant, thereby reducing the chances that adequate bone ingrowth occurs.

Therefore, a need exists for a prosthetic implant that can mimic the density of bone or adequately retain ingrowth material therein to allow for optimal bone ingrowth and provide a solid fusion of the vertebral segments.

SUMMARY

In accordance with an embodiment of the present disclosure, there is provided an interbody spacer including a body portion defining a longitudinal axis. The body portion includes a distal end portion, a proximal end portion, opposed side surfaces that extend between the distal and proximal end portions, and top and bottom surfaces configured and adapted to engage vertebral bodies. The interbody spacer includes first orifices defined through the top surface. The first orifices include orifices having first and second cross-sectional configurations and are arranged in rows extending along the longitudinal axis.

In embodiments, the second cross-sectional configuration may be larger than the first cross-sectional configuration. The first orifices may be arranged in each row of the longitudinal rows in an alternating pattern of orifices having first and second cross-sectional configurations.

In embodiments, the first orifices may include orifices with a third cross-sectional configuration, wherein the third cross-sectional configuration is larger than the second cross-sectional configuration. The first orifices may be arranged in each row of the longitudinal rows in a pattern, such that the cross-sectional configuration of each orifice of the first orifices increases from the first cross-sectional configuration to the third cross-sectional configuration. Alternatively, the first orifices may be arranged in a random pattern.

In embodiments, each orifice of the first orifices may include a cross-sectional configuration selected from the group consisting of arcuate, more than four sides, quadrilateral, triangle, and sinusoidal.

In embodiments, each orifice of the first orifices may include a cross-sectional configuration selected from the group consisting of oval, kidney, elliptical, circular, teardrop, semicircle, and ovoid.

In embodiments, each orifice of the first orifices may include a cross-sectional configuration selected form the group consisting of squircle, square, rhombus, trapezoid, and rectangle.

In embodiments, each orifice of the first orifices may include a cross-sectional configuration selected from the group consisting of hexagon, octagon, heptagon, and pentagon.

In embodiments, each orifice of the first orifices may include a cross-sectional configuration selected from the group consisting of isosceles, equilateral, scalene, arrowhead with arcuate base, and right.

In embodiments, each orifice of the first orifices may include a cross-sectional configuration selected from the group consisting of greek cross and clover.

In embodiments, second orifices may be defined through the bottom surface. One of the first orifices may include a cross-sectional configuration different than that of one of the second orifices. One of the first orifices may be offset from one of the second orifices.

In embodiments, a respective orifice of the first and second orifices may be in open communication, thereby defining a respective channel through the body portion. Each channel includes a cross-sectional configuration that varies in a direction from the top surface to the bottom surface.

In embodiments, each channel may include a sinusoidal cross-sectional configuration. Alternatively, each channel may include a cross-sectional configuration including spherical, cylindrical, frusto conical, ellipsoidal, hyperboloid, or any combination thereof. Alternatively, each channel may include a cross-sectional configuration including helical grooves disposed on an inner wall surface thereof.

In embodiments, a respective orifice of the first orifices may be in open communication with an orifice defined through one of the opposed side surfaces, thereby defining a respective channel through the body portion.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure are described hereinbelow with reference to the drawings, wherein:

FIG. 1 is a rear, perspective view of an interbody spacer provided in accordance with the present disclosure;

FIG. 2, is a side view of the interbody spacer of FIG. 1;

FIG. 3 is a top view of the interbody spacer of FIG. 1;

FIG. 4 is a top view of another embodiment of an interbody spacer similar to the interbody spacer of FIG. 1;

FIG. 5 is a top view of yet another embodiment of an interbody spacer similar to the interbody spacer of FIG. 1;

FIG. 6 is a top view of still another embodiment of an interbody spacer similar to the interbody spacer of FIG. 1;

FIG. 7 is a top view of another embodiment of an interbody spacer similar to the interbody spacer of FIG. 1, without a cavity extending therethrough;

FIG. 8 is a side, cross-sectional, view of the interbody spacer of FIG. 7, taken along section-line 8-8 of FIG. 7;

FIG. 8A is a side, cross-sectional, view of an alternate embodiment of the interbody spacer of FIG. 7, taken along section-line 8-8 of FIG. 7;

FIG. 8B is a side, cross-sectional, view of an alternate embodiment of the interbody spacer of FIG. 8, taken along section-line 8-8 of FIG. 7;

FIG. 9 is an illustration of a family of cross-sectional shapes for an orifice defined through an interbody spacer in accordance with the present disclosure;

FIG. 10 is an illustration of another family of cross-sectional shapes for an orifice defined through an interbody spacer in accordance with the present disclosure;

FIG. 11 is an illustration of yet another family of cross-sectional shapes for an orifice defined through an interbody spacer in accordance with the present disclosure;

FIG. 12 is an illustration of still another family of cross-sectional shapes for an orifice defined through an interbody spacer in accordance with the present disclosure;

FIG. 13 is an illustration of another family of cross-sectional shapes for an orifice defined through an interbody spacer in accordance with the present disclosure;

FIG. 14 is an illustration still another family of cross-sectional shapes for an orifice defined through an interbody spacer in accordance with the present disclosure;

FIG. 15 is an illustration of yet another family of cross-sectional shapes for an orifice defined through an interbody spacer in accordance with the present disclosure;

FIG. 16 is a side, cross-sectional view, of a family shapes for a channel defined through an interbody spacer in accordance with the present disclosure;

FIG. 17 is a side, cross-sectional view, of another family of shapes for a channel defined through an interbody spacer in accordance with the present disclosure;

FIG. 18 is a side, cross-sectional view, of yet another family of shapes for a channel defined through an interbody spacer in accordance with the present disclosure;

FIG. 19 is a side, cross-sectional view, of still another family of shapes for a channel defined through an interbody spacer in accordance with the present disclosure;

FIG. 20 is a side, cross-sectional view, of another family of shapes for a channel defined through an interbody spacer in accordance with the present disclosure;

FIG. 21 is a side, cross-sectional view, of still another family of shapes for a channel defined through an interbody spacer in accordance with the present disclosure;

FIG. 22 is a side, cross-sectional view, of yet another family of shapes for a channel defined through an interbody spacer in accordance with the present disclosure; and

FIG. 23 is a side, cross-sectional view, of still another family of shapes for a channel defined through an interbody spacer in accordance with the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. As commonly known, the term “clinician” refers to a doctor, a nurse, or any other care provider and may include support personnel. Additionally, the term “proximal” refers to the portion of the device or component thereof that is closer to the clinician and the term “distal” refers to the portion of the device or component thereof that is farther from the clinician. In addition, the term “cephalad” is known to indicate a direction toward a patient's head, whereas the term “caudal” indicates a direction toward the patient's feet. Further still, for the purposes of this application, the term “lateral” indicates a direction toward a side of the body of the patient, i.e., away from the middle of the body of the patient. The term “posterior” indicates a direction toward the patient's back, and the term “anterior” indicates a direction toward the patient's front. Additionally, in the drawings and in the description that follows, terms such as front, rear, upper, lower, top, bottom, and similar directional terms are used simply for convenience of description and are not intended to limit the disclosure. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

Referring now to the drawings, FIGS. 1-3 illustrate an interbody spacer provided in accordance with the present disclosure and generally identified by reference numeral 10. Interbody spacer 10 includes a body portion 12 having a substantially contoured first end surface 14 (FIG. 2) at a distal or leading end 16 and a second end surface 18 opposite thereto at a proximal or trailing end 20, having a substantially planar configuration. Axis A-A (FIG. 3) is defined through a midpoint of first and second end surfaces 14, 18, respectively. Body portion 12 extends between first and second end surfaces 14, 18 to define respective top and bottom surfaces 22 and 24 (FIG. 2), respectively, as well as opposed side surfaces 26, 28 (FIG. 3). As best illustrated in FIG. 2, top and bottom surfaces 22, 24 include a generally convex or arcuate profile, each extending in a cephalad and caudal direction (or vice-versa), respectively. Although shown and described as the top surface 22 being oriented in a cephalad direction and the bottom surface 24 being oriented in a caudal direction, the interbody spacer 10 may be positioned such that the top surface 22 is in a caudal orientation and the bottom surface 24 is in a cephalad orientation. As can be appreciated, top and bottom surfaces 22 and 24 may include a concave profile, a planar profile, or any combination thereof. In embodiments, top surface 22 may include a different profile than that of bottom surface 24. Additionally, it is contemplated that top and bottom surfaces 22, 24 may approximate in a direction along axis A-A (or vice-versa), or may approximate in a direction from side surface 26 towards side surface 28 (or vice-versa), or any combination thereof.

As best illustrated in FIG. 3, opposed side surfaces 26, 28 are substantially planar, although other configurations are also contemplated such as convex, concave, or the like. Opposed side surfaces 26, 28 approximate towards each other at distal end 16 along longitudinal axis A-A in order to facilitate insertion within the intervertebral space and enhance the atraumatic character of body portion 12. In this manner, the intersection of top and bottom surfaces 22, 24 with each of first and second end surfaces 14, 18 and opposed side surfaces 26, 28 may include a fillet or rounded configuration 30 to inhibit sharp edges from causing trauma to the surrounding tissue and/or vertebral bodies.

Referring again to FIG. 1, second end surface 18 includes an aperture 32 defined therethrough and extending along longitudinal axis A-A. Aperture 32 is configured for selective engagement with a suitable insertion tool (not shown), such as that described in U.S. Patent Application No. 2012/0158062, filed Oct. 11, 2011, the entire contents of which are hereby incorporated by reference herein. In embodiments, aperture 32 may be threaded or otherwise include various features capable of selectively retaining a suitable insertion tool (not shown) therein, such as a keyhole configuration, quarter-turn configuration, or the like.

Each of opposed side surfaces 26, 28 includes a corresponding depression or recess 26 a, 28 a defined therein adjacent second end surface 18. Recesses 26 a, 28 a extend along longitudinal axis A-A and are symmetrically disposed on each of opposed side surfaces 26, 28 to define a substantially I-shaped configuration to second end surface 18 at proximal end 20. In cooperation with aperture 32, the recesses 26 a, 28 a are further configured to enable engagement with stabilizing jaws of a suitable insertion instrument (not shown) to facilitate the insertion of interbody spacer 10. As can be appreciated, interbody spacer 10 may not include recesses 26 a, 28 a, and rather, include planar side surfaces 26, 28 that extend between first and second end surfaces 14, 18.

Body portion 12 includes a through-bore or cavity 34 defined through top and bottom surfaces 22, 24, respectively. Although shown as having a generally oval configuration, it is contemplated that through-bore 34 may include any suitable shape such as square, rectangular, circular, or the like, or may include a configuration similar to that of the outer perimeter of body portion 12. It is contemplated that through-bore 34 may receive allograft material, autograft material, calcium phosphate/bone marrow aspirate (BMA), autogenous material, synthetic materials comprised of a biocompatible osteoconductive, osteoinductive, or osteogeneic material such as VITOSS® Synthetic Cancellous Bone Void Filler material, or any other suitable biological material known in the art. Through-bore 34 includes a cross-sectional area or surface area that is greater than any orifice of the plurality of orifices or enlarged orifices detailed hereinbelow. In embodiments, through-bore 34 includes a surface area that is equal to or greater than 25% of the surface area of top surface 22 or bottom surface 24.

Top and bottom surfaces 22, 24 of body portion 12 are configured to engage respective endplates of adjacent vertebral bodies. In this manner, each of top and bottom surfaces 22, 24 includes at least first and second surface regions 22 a, 22 b and 24 a, 24 b, respectively, which have distinct surface characteristics. As best illustrated in FIG. 2, first surface regions 22 a, 24 a are disposed distal to second surface regions 22 b, 24 b and include a surface characteristic that is different than that of second surfaces 22 b, 24 b. In embodiments, first surface regions 22 a, 24 a may include a same or similar surface characteristic to that of second surface regions 22 b, 24 b, or each of first and second surface regions 22 a, 24 a and 22 b, 24 b may include the same or different surface characteristics, or any combination thereof.

First surface regions 22 a, 24 a each have a plurality of protrusions (i.e., teeth) or ridges 36 disposed thereof to aid in securing interbody spacer 10 to each respective adjacent vertebral body and stability against fore and aft, oblique or side to side movement of interbody spacer 10 within the intervertebral space. Specifically, protrusions 36 frictionally engage endplates of adjacent vertebral bodies and inhibit movement of the interbody spacer 10 with respect to the adjacent vertebral bodies. In embodiments, a plurality of longitudinal grooves 38 (FIGS. 1 and 3) may be defined within protrusions 36, each of which extends along longitudinal axis A-A. Each of second surface regions 22 b, 24 b includes substantially pyramidal protrusions 40, where each pyramidal protrusion 40 includes a plurality of protrusions or ridges disposed thereon to similarly aid in securing interbody spacer 10 to each respective adjacent vertebral body. In particular, each pyramidal protrusion 40 includes opposed first and second faces that face, respectively, distally and proximally. Further, each pyramidal protrusion 40 has third and fourth faces that face, respectively, medially and laterally. For a detailed description of an interbody spacer having exemplary surface characteristics, reference can be made to U.S. Pat. No. 8,801,791 to Soo et al., filed Sep. 27, 2007, the entire contents of which are hereby incorporated by reference herein.

Interbody spacer 10 is constructed of a biocompatible material, such as commercially pure titanium or titanium alloy and includes a porosity capable of promoting bone ingrowth and fusion with interbody spacer 10. In this manner, top and bottom surfaces 22, 24 and opposed side surfaces 26, 28 have a surface roughness that can promote bone growth and fusion with interbody spacer 10. The surface roughness may be in a range of about 0.10-50 μm, and preferably in a range of about 3-4 μm. As can be appreciated, top and bottom surfaces 22, 24 and opposed side surfaces 26, 28 may include the same or different surface roughness's (i.e., the surface roughness of top surface 22 may be different than the surface roughness of bottom surface 24), or top and bottom surfaces 22, 24 and opposed side surfaces 26, 28 may not include a surface roughness; rather, top and bottom surfaces 22, 24 and opposed side surfaces 26, 28 may be smooth. In embodiments top and bottom surfaces 22, 24 and opposed side surfaces 26, 28 may include any combination of surface roughness or smooth surface. Additionally, body portion 12 includes a plurality of orifices 44 and 46 defined through top and bottom surfaces 22, 24 and opposed side surfaces 26, 28, respectively, configured to promote bone ingrowth. Although illustrated as having a generally circular cross-section, orifices 44 may include any suitable cross-section, as will be described in further detail hereinbelow. Orifices 46 are illustrated as having a generally diamond shaped cross-section, however, it is contemplated that orifices 46 may include any suitable cross-section, as will be described in further detail hereinbelow. The cross-sectional shapes of orifices 44, 46 mimic bone growth along Haversian canals and lamellar structures of bone. The plurality of orifices 44, 46 reduces the density and stiffness of interbody spacer 10 to enable the application of bone putty or the like (e.g., bone-morphogenetic proteins, etc.) to interbody spacer 10 to promote bone ingrowth within interbody spacer 10 and fusion to adjacent vertebral bodies. Bone ingrowth and fusion strengthens interbody spacer 10. In this manner, the likelihood that micromotion would occur would be reduced.

As best illustrated in FIG. 3, the plurality of orifices 44 are arranged in evenly spaced longitudinal rows along longitudinal axis A-A. The plurality of orifices 44 includes orifices with a first diameter 44 a, orifices with a second diameter 44 b, and orifices with a third diameter 44 c. In one non-limiting embodiment, the first diameter 44 a is 30 μm, the second diameter 44 b is 150 μm, and the third diameter 44 c is 500 μm, although other suitable diameters are also contemplated. As can be appreciated, each of the orifices 44 may include a cross-section corresponding to any cross-sectional shape detailed herein. As such, the cross-sectional area of each of orifice 44 a, 44 b, and 44 c may be 0.000707 μm², 0.0177 μm², and 0.196 μm², respectively. In this manner, the plurality of orifices 44 is defined through top and bottoms surfaces 22, 24 and arranged in groups of three orifices, 44 a, 44 b, 44 c, that define a respective pattern along axis A-A of body portion 12.

Referring to FIG. 4, another embodiment of an interbody spacer provided in accordance with the preset disclosure is illustrated and generally identified by reference numeral 110. Interbody spacer 110 is substantially similar to interbody spacer 10, and therefore only the differences therebetween will be described in detail in the interest of brevity. The orifices of the plurality of orifices 144 include orifices with a first diameter 144 a and orifices with a second, larger, diameter 144 b. In one non-limiting embodiment, the diameter of the first diameter 144 a is 150 μm and the diameter of the second diameter 144 b is 500 μm, although other diameters are also contemplated. As can be appreciated, each of the orifices 144 may include a cross-section corresponding to any cross-sectional shape detailed herein. As such, the cross-sectional area of each of orifice 144 a and 144 b may be 0.0177 μm² and 0.196 μm², respectively. In this manner, a pair of rows of orifices 144 having the second, larger diameter 144 b is defined through the distal end 116 of top surface 122 and the bottom surfaces (not shown) and extending in a direction transverse to longitudinal axis A-A. A pair of rows of orifices 144 having the first diameter 144 a is disposed proximal to the pair of rows of orifices 144 having the second, larger diameter 144 b and extends in a direction transverse to longitudinal axis A-A. This pattern is repeated in a proximal (or distal) direction along axis A-A.

With reference to FIG. 5, yet another embodiment of an interbody spacer provided in accordance with the present disclosure is illustrated and generally identified by reference numeral 210. Interbody spacer 210 is substantially similar to interbody spacer 10, and therefore only the differences therebetween will be described in detail in the interest of brevity. The plurality of orifices 244 includes orifices having a first diameter 244 a and orifices having a second, larger, diameter 244 b. In one non-limiting embodiment, the first diameter 244 a is 150 μm and the second diameter 244 b is 500 μm, although other diameters are also contemplated. As can be appreciated, each of the orifices 244 may include a cross-section corresponding to any cross-sectional shape detailed herein. As such, the cross-sectional area of each of orifice 244 a and 244 b may be 0.0177 μm² and 0.196 μm², respectively. In this manner, the plurality of orifices 244 is defined through top and bottom surfaces 222, 224 such that the diameter of the plurality of orifices 244 alternates between orifices having the first diameter 244 a and orifices having the second, larger, diameter 244 b in a direction along longitudinal axis A-A. This pattern is offset in a direction transverse to longitudinal axis A-A such that an orifice of the plurality of orifices 244 having a first diameter 244 a is only adjacent an orifice of the plurality of orifices 244 having a second, larger, diameter 244 b.

With reference to FIG. 6, still another embodiment of an interbody spacer provided in accordance with the present disclosure is illustrated and generally identified by reference numeral 310. Interbody spacer 310 is substantially similar to interbody spacer 10, and therefore only the differences therebetween will be described in detail in the interest of brevity. The plurality of orifices 344 includes orifices of various diameters. In one non-limiting embodiment, the diameter of each orifice of the plurality of orifices 344 may vary between 50 μm and 1000 μm. As can be appreciated, each of the orifices 344 may include a cross-section corresponding to any cross-sectional shape detailed herein. As such, the cross-sectional area of each of orifice 344 may be 0.0707 μm² and 0.385 μm². The plurality of orifices 344 is defined through top surface 322 and the bottom surfaces (not shown) in a random manner such that there are no defined rows, and the diameters of each orifice of the plurality of orifices 344 vary.

Referring now to FIGS. 7 and 8, an alternate embodiment of an interbody spacer provided in accordance with the present disclosure is illustrated and generally identified by reference numeral 410. Interbody spacer 410 is substantially similar to interbody spacer 10, and therefore, only the differences therebetween will be described in detail in the interest of brevity. Interbody spacer 410 does not include a through-bore defined through top surface 422 and the bottom surfaces (not shown). Rather, as best illustrated in FIG. 8, interbody spacer 410 includes a void 448 defined within an interior portion of body 412. In this manner, void 448 does not breach leading or trailing surface 414, 418, top or bottom surface 422, 424, or the opposed side surfaces 426, 428 (FIG. 7). In one non-limiting embodiment, aperture 432 extends through a proximal end of void 448 such that aperture 432 is in open communication therewith. Although illustrated as having a generally circular cross-section, it is contemplated that void 448 may include any suitable shape and/or volume, such as spheroid, ovoid, cuboid, rectanguloid, ellipsoid, or the like. In certain embodiments, void 448 may include an amorphous shape. Additionally, as best illustrated in FIG. 8A, it is contemplated that void 448 may be isolated from the plurality of orifices defined through top surface 422 and the plurality of orifices 446 defined through the opposed side surfaces 426, 428 (FIG. 7), or only one or the other. It is further contemplated that void 448 may include one or more protrusions (not shown) extending towards an interior portion of void 448. As can be appreciated, the one or more protrusions may include any suitable shape, such as frusto conical, spheroid, ovoid, cuboid, rectanguloid, conical, ellipsoid, or the like. By varying the shape and or volume of void 448, the density and stiffness of interbody spacer 410 may be likewise varied, thereby allowing a clinician to select an implant more closely tailored to the density of adjacent vertebral bodies. In embodiments, interbody spacer 448 may include a plurality of smaller voids 448 defined in an interior portion of body 412.

Alternatively, as best illustrated in FIG. 8B, interbody spacer 410 may include no through-bore or void. In this manner, aperture 432 is blind (i.e., terminates in a distal face in an interior portion of interbody spacer 410). Additionally, the plurality of orifices 446 defined through the opposed side surfaces includes a diamond shaped cross-section 446 a on distal and proximal ends 416, 420 and a random array of orifices having a circular cross-section 446 b and varying diameters defined through the opposed side surfaces (not shown) at a medial portion of body 412. As can be appreciated, the plurality of orifices 446 having a diamond-shaped cross-section 446 a may be defined through the medial portion of the opposed side surfaces and the random array of circular orifices 446 b may be defined through distal and proximal ends 416, 420 of the opposed side surfaces, or any combination thereof.

Referring now to FIGS. 9-15, the plurality of orifices 44, 46 may include various cross-sectional shapes of differing families. As illustrated in FIG. 9, orifices 44, 46 may include a cross-sectional shape having varying curvature, designated as a first family 50. Cross-sectional shapes included in first family 50 include oval 50 a, kidney 50 b, elliptical 50 c, circular 50 d, teardrop 50 e, semicircle 50 f, and ovoid 50 g. As can be appreciated, orifices 44, 46 from first family 50 may include any cross-sectional shape having an arcuate, curvate, or otherwise amorphous shape not otherwise illustrated in FIG. 9.

A second family 52 of cross-sectional shapes having more than four sides is illustrated in FIG. 10. In this manner, the plurality of orifices 44, 46 may include a cross-sectional shape of a hexagon 52 a, an octagon 52 b, a heptagon 52 c, and a pentagon 52 d. As can be appreciated, any polygon having more than four sides may be included in second family 52, such as nonagon, decagon, dodecagon, etc.

With reference to FIG. 11, a third family 54 of cross-sectional shapes from which the plurality of orifices 44, 46 may be defined is illustrated. Third family 54 includes quadrilaterals, such as a square with rounded edges 54 a (such as a squircle), square 54 b, rhombus 54 c, trapezoid 54 d, and rectangle 54 e. As can be appreciated, third family 54 may include any quadrilateral, such as parallelogram, kite, isosceles trapezoid, trapezium, etc.

A fourth family 56 of cross-sectional shapes from which the plurality of orifices 44, 46 may be defined is illustrated in FIG. 12. Fourth family 56 includes triangles, such as isosceles 56 a, equilateral 56 b, scalene 56 c, arrowhead with arcuate base 56 d, and right 56 e. As can be appreciated, fourth family 56 may include any type of triangle known in the art.

FIG. 13 illustrates a fifth family 58 of cross-sectional shapes from which the plurality of orifices 44, 46 may be defined. Fifth family 58 includes a greek cross 58 a and clover 58 b, although other similar cross-sectional shapes are contemplated, like, cross, star, or the like.

As illustrated in FIG. 14, a sixth family 60 of cross-sectional shapes from which the plurality of orifices 44, 46 may be defined includes sinusoidal shapes having various lengths, widths, and number of sides. A first sinusoidal shape 60 a includes a width that is larger than that of a second sinusoidal shape 60 b. A third sinusoidal shape 60 c includes pointed opposed ends. As can be appreciated, any suitable sinusoidal shape may be included in sixth family 60.

FIG. 15 illustrates a seventh family 62 of cross-sectional shapes from which the plurality of orifices 44, 46 may be defined. The cross-sectional shapes included in the seventh family 62 include ornate designs having various circular designs as illustrated in first design 62 a or rectangular designs as illustrated in second design 62 b. First design 62 a includes upper and lower apertures 62 aa and 62 ab defining a generally oval shape. First design 62 a includes a plurality of additional bores 62 ac defined in an interior portion thereof. In this manner, a plurality of circular features resembling wheels and spokes and/or pinwheels are defined. The plurality of bores 62 ac define a corresponding plurality of bridges or spokes 62 ad that separate each of each of the upper and lower apertures 62 aa, 62 ab, and plurality of bores 62 ac.

Similarly, second design 62 b includes upper and lower apertures 62 ba and 62 bb defining a generally rectangular shape. A plurality of elongate, arcuate, bores 62 bc are defined in an interior portion of second design 62 b, the plurality of elongate, arcuate, bores 62 bc defining cooperating to define a generally triangular shape. The plurality of elongate, arcuate, bores 62 bc define a corresponding plurality of bridges 62 bd that separate each of the upper and lower apertures 62 ba, 62 bb and plurality of bores 62 bc.

As can be appreciated, any of the above described families may be interchanged or randomly selected as the cross-sectional shape of orifices 44, 46 defined through upper and lower surfaces 22, 24 or opposed side surfaces 26, 28, respectively, of body portion 12. In embodiments, the plurality of orifices 44 defined through top surface 22 may utilize a different cross-sectional shape than that of the plurality of orifices 44 defined through bottom surface 24. Similarly, the plurality of orifices 46 defined through side surface 26 may include a different cross-sectional shape than the plurality of orifices 46 defined through opposite side surface 28. It is contemplated that any number of combinations of cross-sectional shapes may be employed.

Referring now to FIGS. 16-23, the plurality of orifices 44, 46 defined through top and bottom surfaces 22, 24 and opposed side surfaces 26, 28 define a respective channel through body portion 12. FIGS. 16-23 illustrate a variety of families of channels that may be defined through body portion 12. As best illustrated in FIG. 16, a first family of channels 64 having a generally arcuate profile is illustrated. The first family of channels 64 includes a first channel 64 a having a generally arcuate profile. First channel 64 a includes a pair of bowed or bulging sidewalls and includes a constant width. A second channel 64 b includes a generally sinusoidal profile. A third channel 64 c includes a pair of channels 64 ca, 64 cb defining a generally X-shaped configuration. In this manner, channel 64 ca of the pair of channels is bowed in a first direction and channel 64 cb of the pair of channels bows in an opposite direction, such that channels 64 ca, 64 cb intersect (i.e., channels 64 ca and 64 cb are in open communication). A fourth channel 64 d includes a generally hourglass profile. A fifth channel 64 e includes an elliptical profile. As can be appreciated, first family of channels 64 may include any suitable profile having arcuate sidewalls.

FIG. 17 illustrates a second family of channels 66 having generally planar sidewalls. First channel 66 a includes planar sidewalls extending in a diagonal direction such that the openings of an orifice of the plurality of orifices 44, 46 on the top and bottom surfaces 22, 24, respectively, are offset in relation to one another. A second channel 66 b includes a generally arrowhead or rotated chevron type profile (i.e., upper and lower portions extending diagonally toward one another in a medial portion of body portion 12 to define a point). A third channel 66 c includes a generally hourglass profile having planar sidewalls. A fourth channel 66 d includes a generally inverted hourglass profile (i.e., the width of fourth channel 66 d increases at a middle portion thereof).

A third family of channels 68 is illustrated in FIG. 18. Each channel of the third family of channels 68 is mirrored about axis B-B defined at a medial portion of body 12. A first channel 68 a is defined through top surface 22 and includes a first cylinder 68 aa having a first diameter extending towards bottom surface 24. First cylinder 68 aa transitions to a second cylinder 68 ab and includes a second, larger, diameter than the diameter of first cylinder 68 aa. A second channel 68 b is essentially an inverse of first channel 68 a. In particular, a first cylinder 68 ba having a first diameter intersects top surface 22 and extends towards bottom surface 24. First cylinder 68 ba transitions to a second cylinder 68 bb and includes a second, smaller, diameter than the diameter of first cylinder 68 ba.

Referring now to FIG. 19, a fourth family of channels 70 is illustrated. A first channel 70 a is defined through top surface 22 of body portion 12 and includes a generally arcuate shape such that first channel 70 a curves towards, and extends through, one of opposed side surfaces 26, 28. A second channel 70 b is defined through bottom surface 24 of body portion 12 and includes a generally arcuate shape such that second channel 70 b curves towards, and extends through, an opposite one of opposed side surfaces 26, 28 than that of first channel 70 a.

FIG. 20 illustrates a fifth family of channels 72 including similar profile to that of the fourth family of channels 70. In this manner, a first channel 72 a includes a tighter radius of curvature than that of a second, opposed channel 72 b. As can be appreciated, second channel 72 b may have a tighter radius than that of first channel 72 a.

A sixth family of channels is illustrated in FIG. 21 and is generally identified by reference numeral 74. Each channel of the third family of channels 74 is mirrored about axis B-B defined at a medial portion of body 12. A first channel 74 a includes a frusto conical profile 74 aa defined through top surface 22 of body portion 12 extending towards bottom surface 24. Frusto conical profile 74 aa includes a generally inverted orientation (i.e., the diameter decreases in a direction from top surface 22 towards bottom surface 24). Frusto conical profile 74 aa transitions to a cylindrical profile 74 ab at a medial portion of body portion 12 having a larger diameter than that of the portion of frusto conical profile 74 aa that intersect cylindrical profile 74 ab.

A second channel 74 b includes a substantially similar profile to that of first channel 74 a except that the frusto conical profile 74 ba is inverted with respect to frusto conical profiles 74 aa of first channel 74 a.

Third channel 74 c includes first portion 74 ca having a generally hourglass configuration that intersects top surface 22 of body portion 12 and extends towards bottom surface 24. First portion 74 ca transitions to a second portion 74 cb having a generally cylindrical configuration at a medial portion of body portion 12.

A fourth channel 74 d includes a first portion 74 da having a generally spherical configuration. First portion 74 da is defined through top surface 22 of body portion 12 and extends towards bottom surface 24. First portion 74 da transitions to a second portion 74 db having a generally cylindrical configuration at a medial portion of body portion 12. Second portion 74 db includes a diameter less than the diameter of first portion 74 da.

FIG. 22 illustrates a seventh family of channels generally identified by reference numeral 76. Each channel of the third family of channels 76 is mirrored about axis B-B defined at a medial portion of body 12. A first channel 76 a includes a first and second spherical portion 76 aa and 76 ab respectively, disposed in a generally stacked configuration such that first spherical portion extends through upper surface 22 of body 12. Each of first and second spherical portions 76 aa and 76 ab include a generally similar diameter, although other configurations are also contemplated.

A second channel 76 b includes a first portion 76 ba defined through top surface 22 of body portion 12 and extending towards bottom surface 24. First portion 76 ba includes a generally cylindrical configuration and transitions to a second portion 76 bb having a generally spherical configuration at a medial portion of body portion 12.

Third channel 76 c includes a first portion 76 ca having a generally inverted frusto conical configuration (i.e., the diameter of first portion decreases in a direction from top surface 22 towards bottom surface 24). First portion 76 ca is defined through top surface 22 of body portion 12 and extends towards bottom surface 24. First portion 76 ca transitions to a second portion 76 cb having a generally ellipsoid configuration at a medial portion of body portion 12, although it is contemplated that second portion 76 cb may include a generally spherical configuration similar to that of second portion 76 bb of second channel 76 b.

Fourth channel 76 d is similar to that of third channel 76 c except that the first portions 76 da includes a frusto conical configuration that is inverted relative to first portion 76 ca of third channel 76 c. Second portion 76 db includes a generally spherical configuration.

A fifth channel 76 e includes a first portion 76 ea having a generally hourglass configuration. First portion 76 ea is defined through top surface 22 of body portion 12 and extends towards bottom surface 24. First portion 76 ea transitions to a second portion 76 eb having a generally spherical configuration at a medial portion of body portion 12.

FIG. 23 illustrates an eighth channel 78 defined through top and bottom surfaces 22, 24 of body portion 12. Eighth channel 78 includes a generally cylindrical profile including helical grooves 78 b defined on an inner sidewall 78 a thereof.

Although each orifice and channel has been hereinabove described as being defined through top and bottom surfaces 22, 24 of body 12, as can be appreciated, the orifices and channels may be defined through opposed side surfaces 26, 28.

As can be appreciated, manufacturing interbody spacers 10, 110, 210, 310, and 410 using standard machining methods (e.g., lathe, mill, EDM, etc.) could be difficult. In view of this, it is contemplated that in addition to manufacturing interbody spacers 10, 110, 210, 310, and 410 using the aforementioned conventional means, interbody spacers 10, 110, 210, 310, and 410 may be manufactured by means of additive manufacturing methods (e.g., SDM, SLPP, DMLS (i.e., EOS), SLS, SLM, SHS, EBM, VAT photopolymerisation, material jetting, binder jetting, or the like). In one non-limiting embodiment, interbody spacers 10, 110, 210, 310, and 410 may be manufactured using Selective Laser Powder Processing (SLPP). SLPP utilizes powdered metal and a laser which sinters or cures the metal in a selective fashion according to the design intent in thin layers. In embodiments, the layers have a thickness of about 250 μm. Interbody spacers 10, 110, 210, 310, and 410 are built layer by layer to allow for more design options and features that would be difficult to be machined using conventional methods. Specifically, a first layer of powder is applied to a specialized build plate, at which point the laser cures portions of the powder according to the design intent. At this point, a second layer is applied to the build plate and the laser is again used to cure selective portions of this second layer. This process is repeated until interbody spacers 10, 110, 210, 310, and 410 are fully formed. Once interbody spacers 10, 110, 210, 310, and 410 are fully formed, uncured powder is removed using compressed air or other similar means. Next, post machining is performed on interbody spacers 10, 110, 210, 310, and 410 to remove any burrs or similar imperfections embedded within interbody spacers 10, 110, 210, 310, and 410 during the additive manufacturing process. In embodiments, the burrs are removed by means of buffer wheels, clippers, files, or the like. Once de-burred, interbody spacers 10, 110, 210, 310, and 410 are heat treated, and thereafter, media blasted using aluminum oxide. Thereafter, interbody spacers 10, 110, 210, 310, and 410 are immersed in a hydrofluoric bath to strip the aluminum oxide therefrom. Finally, interbody spacers 10, 110, 210, 310, and 410 are inspected by quality control personnel (or using automated means), cleaned via ultrasonic cleaning, dried, and packaged. It is contemplated that the design of interbody spacers 10, 110, 210, 310, and 410 may be customized for each specific patient using SLPP. For a detailed description of exemplary manufacturing methods, reference may be made to U.S. Pat. No. 8,590,157, issued on Nov. 26, 2013 to Kruth et al., the entire contents of which are hereby incorporated by reference herein.

Interbody spacers 10, 110, 210, 310, and 410 may be constructed from commercially pure titanium, titanium alloy, cobalt-chrome, ceramic, Polyetheretherketone (PEEK), or any other suitable biocompatible material. In embodiments, interbody spacers 10, 110, 210, 310, and 410 may be manufactured using a three-dimensional printer utilizing a biocompatible polymer.

With reference to FIGS. 1-8B, in use, an intervertebral space is first prepared, e.g., damaged or diseased tissue is removed. As the construction of interbody spacer 10 is similar to that of interbody spacers 110, 210, 310, and 410, only the method of use of interbody spacer 10 will be described in detail for purposes of brevity. An appropriately sized interbody spacer 10 is selected based on the patient's spinal characteristics and the desired amount of lordosis. Next, the interior space of through-bore 34 of body portion 12 may be packed with bone in-growth material, drugs, or other suitable materials or compounds. Examples of such materials are allograft material, or synthetic materials comprised of a biocompatible, osteoconductive, osteoinductive, or osteogeneic material such as VITOSS® Synthetic Cancellous Bone Void Filler material. Next, a suitable insertion instrument (not shown) is threaded into aperture 32 of body portion 12 until interbody spacer 10 is securely affixed to the insertion instrument. At this point, interbody spacer 10 is advanced within an incision within the patient, and thereafter, the previously prepared inverterterbal space of the patient's spine. Once interbody spacer 10 is placed within the intervertebral space such that interbody spacer 10 rests on the distal apophyseal ring of the vertebral body, the tool (not shown) is released from aperture 32, and thereafter, the incision within the patient. By residing on the apophyseal ring, interbody spacer 10 is less likely to experience subsidence into the end plates which will facilitate fusion between the intervertebral plates.

This process may be repeated as many times as the procedure requires, whether it be for the same interbody spacer 10 or for a plurality of interbody spacers 10 as required by the procedure being performed.

It is envisioned that the manufacturing processes and orifice designs detailed above may be utilized to form various other medical devices known in the art. In this manner, the additive manufacturing process detailed above may be employed to form corpectomy devices, fixed spinal implants, expandable spinal implants, bone screws, cervical implants, and the like. Similarly, the orifice designs detailed above may be formed in any of the beforementioned medical devices that would benefit from an increased ability to fuse with bone. Examples of such devices may be found in the following commonly owned references: U.S. Pat. No. 8,585,761 to Theofilos, U.S. Pat. No. 8,673,011 to Theofilos et al., U.S. application Ser. NO. 14/936,911 to Sutterlin et al., U.S. Pat. No. 8,801,791 to Soo et al., U.S. Pat. No. 8,439,977 to Kostuik et al., U.S. Patent Application Publication No. 2010/0100131 to Wallenstein, U.S. Patent Application Publication No. 2012/0179261 to Soo, U.S. Pat. No. 8,449,585 to Wallenstein et al., U.S. Pat. No. 8,814,919 to Barrus et al., U.S. Pat. No. 5,733,286 to Errico et al., and U.S. Patent Application Publication No. 2013/0046345 to Jones et al.

It will be understood that various modifications may be made to the embodiments of the presently disclosed interbody spacer. Therefore, the above description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure. 

What is claimed is:
 1. An interbody spacer, comprising: a homogenous body portion including a distal end portion, a proximal end portion, opposed side surfaces that extend between the distal and proximal end portions, and top and bottom surfaces configured and adapted to engage vertebral bodies, the top and bottom surfaces defining a vertical axis extending therethrough; first orifices defined through the top surface; and second orifices defined through the bottom surface, wherein a respective orifice of the first and second orifices is in open communication thereby defining an uninterrupted channel therebetween, wherein the channel defines a plurality of cross-sections, a center cross-section of the plurality of cross-sections defining a cross-sectional area that is less than cross-sections disposed adjacent the top surface and the bottom surface.
 2. The interbody spacer of claim 1, wherein the body portion is formed from powder processed using Selective Laser Powder Processing.
 3. An interbody spacer comprising: a monolithic body portion having opposed proximal and distal end portions, opposed top and bottom surfaces, and opposed side surfaces extending between the top and bottom surfaces and between the proximal and distal end portions; a first orifice extending through the top surface; a second orifice extending through the bottom surface, the first and second orifices coincident about a first vertical axis, a first channel extending between the first and second orifices, the first channel being connected to a third orifice extending through the top surface; and a second channel extending between the third orifice and a fourth orifice, the fourth orifice extending through the bottom surface, wherein the first channel is in fluid communication with the second channel.
 4. The interbody spacer of claim 3, wherein a-the first vertical axis extends between the first orifice and the second orifice, a midpoint of the first channel being laterally spaced from the first vertical axis.
 5. The interbody spacer of claim 3, wherein the body portion is formed from powder processed using Selective Laser Powder Processing.
 6. The interbody spacer of claim 4, wherein a second vertical axis extends between the third orifice and the fourth orifice, a midpoint of the second channel being laterally spaced from the second vertical axis. 